Using of wxWidgets 3.1.6 WIP:

* Create Cache of wxBitmapBundles instead of wxBitmaps
* Use wxBitmapBundles instead of wxBitmap for most of Widgets
* Use empty bitmabundles instead of wxNullBitmap for wxBitmapComboBoxes.
* Updated wxWidgets.cmake
* OSX specific: Discard BitmapComboBox overrides
+ some code cleaning

src/slic3r/GUI/GUI_ObjectList.cpp

@@ -4239,9 +4239,6 @@ void ObjectList::msw_rescale()
     GetColumn(colExtruder)->SetWidth( 8 * em);
     GetColumn(colEditing )->SetWidth( 3 * em);
 
-    // rescale/update existing items with bitmaps
-    m_objects_model->Rescale();
-
     Layout();
 }
 
@@ -4249,7 +4246,10 @@ void ObjectList::sys_color_changed()
 {
     wxGetApp().UpdateDVCDarkUI(this, true);
 
-    msw_rescale();
+    // update existing items with bitmaps
+    m_objects_model->UpdateBitmaps();
+
+    Layout();
 }
 
 void ObjectList::ItemValueChanged(wxDataViewEvent &event)